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Final Project – More updates

Our final project is coming along great so far. The biggest change we have introduced is switching to the Polar heart band instead of the electrodes and AD8232 heart monitor we started with. We found a second circuit in the data sheet that would filter noise. It was hard to follow tiny traces and components on the sparkfun breakout board.

Even after modifying the the AD8232 breakout board to the heavy noise filtering circuit, we were still unable to get a reliable signal

After extensive research, we learned that in order to monitor the tiny voltages associated with heart rate reliably during movement, we would need an accelerometer to get movement data to process and filter noise from the signal. Luckily a product exists that takes care of a lot of this front-end work already: the Polar heart band!

The polar band is able to send a reliable heart pulse even during movement

The polar sends a low frequency 16ms pulse for every heartbeat. We receive this with a proprietary polar receiver, which then pulls an input pin high on the wearable moteino for every beat.

This beat happens a little fast for p5, so we increase its duration to 320ms before outputting it to serial: